Question

If I have a set of branches with common ancestor commit a, is there an easy way to rebase all of them onto commit b (where the common ancestor of a and b might be some third commit c)?

Answer 1

Yes. Just rebase them all.

If you anticipate repeated conflicts, enable git-rerere, which records your conflict resolutions and is able to automatically apply the same resolution when merge encounters the exact same conflicts in another (re)merge.

• see http://progit.org/2010/03/08/rerere.html

Or you could,

1. Isolate commit a in a branch

    git checkout -b temporary <commita>
   

2. Rebase the temporary branch onto commit b.

3. Rebase all the ‘related’ branches onto the resulting branch temporary